CMS SOM App. H, Tag V252

7.2 Microbial monitoring methods

7.2.1 General

7.2.2 Sample collection

7.2.1 General

Culture water …weekly for new systems until a pattern has been established. For

established systems, culture monthly unless a greater frequency is dictated by historical

data at a given institution.

Monitoring can be accomplished by direct plate counts, in conjunction with the

measurement of bacterial endotoxin.

7.2.2 Sample collection

Water samples should be collected directly from outlet taps situated in different parts of

the water distribution system. In general, the sample taps should be opened and the water

should be allowed to run for at least 60 seconds before a sample is collected in a sterile,

endotoxin-free container. A minimum of 50 mL of water, or the volume specified by the

laboratory performing the test, should be collected. Sample taps should not be disinfected.

Interpretive Guidance § 494.40(a)

ANSI/AAMI RD52:2004

7.2.2 Sample collection

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All new sterile plastic ware is endotoxin-free because of the high temperatures involved in the

manufacturing process.

Additional Guidance:

Bacterial colony counts may be done by an outside lab (thus the reference to direct plate counts)

or by the use of dip samplers, as described at V256. If a pattern of results greater than the

accepted limits is identified, the frequency of cultures (and subsequent disinfection) should be

increased to reach a frequency that ensures the system is being maintained below the allowed

contamination level between scheduled sampling. Refer to V255.